The principal goal of this SBIR Phase II proposal is to establish the clinical value of a novel prostate cancer (PCa) non-aggressiveness biomarker present in various physiological samples e.g. Prostatic Fluids, (PFs), Expressed Prostatic Secretions, (EPS), or Post-Massage Urine samples, (PMUs). Once statistically validated in this study (n=841), this non-aggressiveness biomarker will be the basis of a reliable and innovative prognostic test that will complement the current clinical guidelines for active surveillance alread established by the National Comprehensive Cancer Network (NCCN).6 Greater screening rates in conjunction with improved detection methods have resulted in a controversial upsurge in the number of men undergoing prostate biopsy and subsequent treatments.7 Upon diagnosis of PCa, physicians and patients typically choose clinical interventions, despite evidence that intervention is not always warranted, especially for low-risk, non-aggressive cancers.4 The negative side effects of these interventions, which may include, incontinence, impotence and bowel dysfunction are perpetuating the controversy of PCa overdiagnosis & overtreatment attributed to increased screening.10 Recent recommendations from the U.S. Preventative Services Task Force (USPSTF) and the American Urology , Association (AUA), to discontinue routine PSA screening, have further fueled the controversy.8 9 However, these recommendations for reducing screening have created concern about the potential uptick in mortality from missed cancers. Recent academic studies suggest that the enzymatically active isoform of PSA plays a significant role in tumor invasion and metastasis.11 In Phase I and subsequent studies, Ohmx found the level of PSA Peptidase Activity (PPA) in prostatic fluid and expressed prostatic secretions to be inversely proportional to disease stage, such that patients with the non-aggressive PCa have on average significantly increased PPA levels compared to those with more aggressive disease.5 Significantly, preliminary results suggest many (22% in an initial study population n=100) of the diagnosed patients with non-aggressive PCa could have averted or delayed radical prostatectomy. Ohmx is proposing a paradigm shift that complements screening techniques and provides a prognostic test that can directly aid in the refinement of treatment decisions. A non-aggressive test result reduces the number of unnecessary clinical interventions, thereby maintaining the patient's quality of life, while reducing overall healthcare costs. This innovative test will enhance the differentiation of non-aggressive cancer, and in conjunction with recent NCCN guidelines (based on biopsy stage, Gleason score, PSA results and the age of the patient) 6 will increase patients' acceptance of active surveillance and confidence in risk stratification for delaying treatment.